Process for producing dehydroperillic acid



Feb. 13, 1951 w. G, VAN BEcKUM PROCESS FOR PRoDucING DEHYDRGPERILLICACID Filed June 17f 1948 MMl m Il E. tEu

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INVENTOR. W/LL/AM G Vd/V BEC/(UM ATTORNE YS Patented Feb. 13, 1951PROCESS FOR PRODUCIN G DEHYDRO- PERILLIC ACID William G. Van Beckum,Longview, Wash., as-

signor to Weyerhaeuser Timber Company, Longview, Wash., a corporation ofWashington Application .lune 17, 1948, Serial No. 33,638

(Cl. 26th-,124)

6 Claims.

`rIhis invention relates to a process for the production of an organicacid, and more particularly pertains to a process for the productionfrom lignocellulose materials of an organic acid heretofore identifiedand known as dehydroperillic acid. The `process of the invention isparticularly applicable to the production of the said acid as aby-product of a commercially feasible process for the production oflienin from aqueous alkaline extracts resulting from the treatment offiber derived from certain species of woods with a dilute aqueoussolution of an alkali metal hydroxide, This application is acontinuation-inpart ofabandoned application Serial No. 602,916, filedJulytZ, 1945.

yThe properties of the acidic compound which isa product of the processof the invention indicate that it may be an analogue of perillic acid,diferingftherefrom in that it contains one additional double bond in itsmolecular structure. It has, therefore, been tentatively nameddehydroperillic acid (cf. Journal of the American ChemicalrSociety, v.55:3813-9 (1933)). The relationship between the two compounds is clearlyevident from the following structural formulas:

Formula I Coon t 112C/ C\ C@ CH2 lFertilia acid `Formula, II

,Icoon When wood is used as a source material for the production ofdehydroperillic acid in accordance with the herein described process, itis preferablyiirst reduced to Afibrous form by mechanical or othermethods which do not subject the wood to the action of added chemicalsother than Water. This reduction is carried to the point Where itresultsin the conversion of -the wood substance to bers `physicallyconsistingsubstantially of ultimate fibers and opened-up bundles ofultimate bers and constitutionally consisting primarily of cellulose,lignin, and polysaccharides-other-than-cellulose, `hereinfrequentlyreferredto merely as .polysacoharides, these threeconstituents being present in mutual ratios in the range of contentsfalling `between that characterizingthe raw Wood from which the fiber isderived and that characterizing .the water-insoluble content .of the raw.Woodfrorn which the fiber is derived. .Fiber containing ce1- lulose,lignin, and polysaccharides-other-thancellulose in the rangecharacterizing the Waterinsoluble content ci .the raw `vvood `from whichthe ber is .derived is exemplied by raw Wood ber which has been sotreated with water as to extract the water-soluble constituents andleave as' a fibrous `residue the Water-insoluble content of the wood.The production of such ber from Woods such as western larch isof`particular interest, since these `woods Acontain high percentages ofWater extractablesubstances.. as. about, 23% in the case of westernlarch. It may, therefore, be commercially desirable in the case of thesewoods to extract them with Water in order to isolate vas commercialproducts the water-soluble fraction of the wood substance. Aiiberresidue is thus obtained which maybe employed to advantage as a rawmaterial for the fractionation process` of the instant invention.

The wood fibers to which the process or" the invention maysatisfactorily be applied may be produced, for example, bythe methoddescribed in United States Letters Patent No.71,913,607 to McMillan.This patent describes a mechanical debering process entirely free fromchemical action, which comprises combing out substantially ultimate bersfrom Wood by contacting logs of wood With high speed rotary radialelements such as pointed pins projecting` from an axle, like bristles.Fiber produced .by this process is herein referred to as McMillan ber,or pin fiber.

Wood ber suitable for use in the process of the present invention mayalso be prepared by themethod described in the United States LettersPatent No. 2,668,892 to Asplund. In this method Wood substance isdebered by mechanically reducing the Wood While simultaneously applyingsufficient steam `pressure to soften the lignin in the middle1amel1a',lthus permitting easy debrationof the softened wood. The berre-` 3 sulting from this practice in ecient operation of the commercialAsplund machine is termed herein normal Asplund fiber, or normaldeiibrator ber. wood while exposing it for about one minute to highpressure steam at a temperature sun'cient to eiect the desiredsoftening.

Other processes may be employed for reducing wood substance to saidultimate nbersor openedup bundle form. The Wood substance may beaffected by steam at any time or times before, during or after suchdeilbration. Action by steam should be such as to avoid any substantialgasication of the Wood substance which thus leads to lossordecomposition of Wood substance, usually with the formation oi'furiural, as well as to a1- tered proportions or" the three primaryconstituents, and unduly altered forms of said constituents. The bersresulting from processes involving both debering and steaming, whichincludes those resulting from the Asplund process, differ from the raWWood in that their Water-soluble content has been to a greater or lesserdegree increased by the action of the steam. In the case of normalAsplund aspen bers made in about one minute at about 128 pounds Ysteampressure, the increase in Water-soluble content is 4% to 6%.

Other methods for producing fibers from Wood substance may also be used,provided said methods do not subject the wood to the action of addedchemical agents other than liquid Water or steam.

It has been discovered that dehydroperillic acid may be obtained bysubjecting lignocellulose materials which contain it 'to the action of adilute aqueous solution of a basic-acting compound of an alkali metal,separating the treated material from the resulting solution, andisolating from the said resulting solution its content ofdehydroperillic acid.

More specifically stated,.dehydroperillic acid is obtained fromlignocellulose materials, e.g. VWood ber, in accordance with the processof the present invention, by treating such materials with an aqueousalkaline reagent preferably comprising a Weak aqueous solution of analkali metal hydrox.

ide, e. g. sodium hydroxide, at an elevated temperature for a timesufficient substantially to exhaust the extracting action of the alkali,thereby forming a solution comprising dehydroperillic acid,polysaccharides-other-than-cellulose, and lignin, and leaving a brousresidue, separating the said solution from the said residue, andconcentrating and acidiiying the said solution in order to separatetherefrom its dehydroperillic content.

. A specific embodiment of the invention for obtaining dehydroperillicacid from lignocellulose material is illustrated in the drawing. Inaccordance with the procedure therein outlined, lignocellulose material,e. g. the liber ofv western red cedar, indicated at 7, containingsubstantially all of the Water-insoluble content of the wood from whichthe iiber is derived, and prepared by the heerinabove referred toAsplund, McMillan or other processes, and physically consistingsubstantially of ultimate bers and opened-up bundles of ultimate bersand constitutionally consisting primarily of cellulose, lignin, andpolyl saccharides-other-than-cellulose, said three con- Y treated at 8with an'alkaline reacting` compound of. alkali-metal. The alkalinereagent employed is It is prepared, for example, by reducing.

typically exemplied by sodium hydroxide, e. g; a

-1/4 normal solution of alkali-metal hydroxide, in

a total amount with respect to ber sufficient to maintain an extractingalkalinity during the operation. This treatment is preferably carriedout at atmospheric pressure and at about the boiling point of the saidsolution. The time of treatment is Variable depending upon the type ofWood being treated and the' other conditions of the treatment,

but, in general, may be up to about two hours, or Y such time as showsthe extraction to be substantially complete.r This treatment extractsfrom the Wood substance the dehydroperillic acid as Well as asubstantial proportion of the lignin andpolysaccharides-other-than-cellulose content and leaves a brous residue.The reactedY mass is extracted at step IG to separate the solublematterfrom the thus, treated fiber. Y

Step e may be practiced by a batchwise procedure or by a counter-currentor recycling pro-- cedure as hereinafter more `fully discussed. Water isusually employed as the solvent in step IS, but the water may also beadmixed with other materials in order to contribute specific propertiesto the solvent or for specic purposes. Water alone, or With suchothergmaterials admixed therein, is herein referredto as an aqueousVsolvent. Steps 3 and iil may be eiiiciently combined when an aqueoussolution of sodium hydroxideY `or solution I5, arbitrarily hereindesignated Extract I, which contains the dehydroperillic acid,

lignin and the other organic materials including thepolysaccharides-other-than-cellulose.

After separation of the said residue I3 from the lextract 25, thesaid-extract is treated for isolation of its dehydroperillic acidcontent. It is rst neutralized at step IS, preferably by adding sulfurieacid, thereby reducing the pH from an original value of about 10 to oneof about 7. The

. solution as thus acidified is then conditioned for precipitation atstep I8. .This conditioning may take one of tvvo forms, or a combinationof both by either the removal of water of solution, step 2li, or by theaddition-of inorganic salts, step 22. Both treatments have in common thefact that they result in the concentration of the solution to a point atwhich completion of the lignin precipitation is eiected. Theprecipitated lignin is then iiltered at step 24 and recovered at 25 asproduct lignin l-a.

It is desired at this point to elaborate on step it of conditioning thesolution for precipitation of thelignin, especially since this same stepis generally applicable at other steps in the process, or in othersequences, to the separation of theV other lignin products at other pI-Iranges. Y While,

some precipitation of lignin may occur by virtue of establishment of thepH range for separationi of the lignin product concerned, the separationof the lignin in this manner is not sharp, and it is advisable tocondition the solution inorderto.

eiect the complete precipitation of all the lignin which Will separateat the particular pI-I range.

tinlied to a point Where thelignin content is precipitated insubstantial amount. The solution is preferably maintained neutr-alduring the concentration step by the addition of acid as necessary. I-twill be obvious that the need for concentration by removal of water willdepend upon the usage ofalkali and-the concentration of the alkali inthe solution i5. The more the salt content formed by the interactionbetween the alkali and the acid, the less will be the extent to whichthe removal of water needs to be continued. t will be furtherappreciated in this connection that steps iii and i8 are more or lessinterdependent and that either'step may be performed first; that is,either the removal of water or the addition of the salt may precedeacidification. It is generally more advantageous, however, for step I8to follow step I6, because, in this manner, full advantage can be takenof the salts formed by the neutralization of the alkali present.

When the conditioning of the solution for precipitation is to beaccomplished by the addition of inorganic salts as at 22, sodium acidsulfate is preferably used, and is added until the solution is nearsaturation with respect to this compound. At this point, precipitationof lignin 1-a can be expected to be substantially complete. The neutral,concentrated solution containing undissolved lignin, preferably at roomtemperature, is filtered at 2d, thereby separating lignin l-a,designated at 25, in the solid form.

The filtrate 26, which contains the dehydroperillic acid in salt" formtogether with the polysaccharides-other-than-cellulose and additionallignin products, is next acidified to a pH of about 5 at step 2l'. Thiscauses the precipitation of the dehydroperillic acid together with anadditional lignin product. The resulting mixture is then warmed to atemperature of about 65 C. at step 28 in order to ccagulate the ligninproduct and effect its separation from the dehydroperillic acid. Uponcooling, the coagulated lignin product is to be found in large partsettled out on the bottom of the containing vessel, while thesupernatant liquid contains suspended crystals of dehydroperillic acidtogether with a line suspension of lignin product particles. Since theparticle size of the dehydroperillic acid crystals is substantiallygreater than that of the suspended lignin product particles, it ispossible to eifect the separation thereof, as by decanting thesupernatant liquor fromthe coagulated lignin product remaining in thevessel, the said supernatant liquor being passed through a ltering meanswhereof the mesh size is such as to permit passage of the iine particlesof suspendedV lignin product, but to retain the larger dehydroperillicacid crystals. This is represented at step29. This results' in theformation of a ltrate 3l, which contains lignin products in aqueoussolution and in suspension, together withpolysaccharides-other-than-cellulose in aqueous solution, and, as asolid product inV cake form, the crude dehydroperillic acid 32. Thisacid may be refined, as by washing with cold Water, at step 33 to give apurified dehydroperillic acid product 34, while the filtrate 3| may beprocessed to isolate valuable polysaccharidesother-than-cellulose andlignin products therefrom.

It will be apparent that the operating conditions a`s described in thepreferred embodiment may be varied as desirable or necessary whenprocessing different types of lignocellulose materials or employing arange 'of reagent concentrations. For example, various alkaline'materials may be employedin the treating step' 8; Suitable" alkalineVmaterials include in general the hydroxides of the alkali metals aswell as those alkali metal compounds which, being salts of strong basesand weak acids, undergo hydrolysis in aqueous medium to form the alkalimetal hydroxides, or their equivalent in alkali metal ions and hydroxylions. Such compounds are, therefore, the basic-acting compounds of the.alkali metals, i. e. of lithium, sodium, potassium, rubidium, andcaesium. The hydroxides of this group of metals, especially sodiumhydroxide, are preferred reagents for effecting the herein describedextraction, although the carbonates, e. g. sodium carbonate, may also beused.

Similarly, the operating conditions of the extraction step, wherein thelignocellulose material is treated with a dilute aqueous solution ofalkali, may be varied within limits to suit the particularlignocellulose material being treated. It is the teaching of theinvention, however, and often critical to its success in practice, touse and maintain operating conditions and reagents of such a mildcharacter as to effect the fractionation of the lignocellulose materialswithout causing substantial or drastic changes in the composition of theconstituents thereof. Thus, it is preferred to use a relatively WeakVsolution of alkali, i. e., a solution which contains suiicient alkalito be about 1/4 normal with respect thereto. A preferred solution foreffecting the extraction is a 0.6% solution of sodium hydroxide.

Usages of alkali-largely in excess of those necessary to obtain thedesired fractionation are also avoided. The total amount of alkali metalhydroxide used is usually based upon the weight of fiber treated. Thus,for example, a usage of 15% sodium hydroxide signies that l5 parts byweight of sodium hydroxide is used to extract parts of dry ber.

Where a mixing procedure is employed in the extraction with alkali metalhydroxide, the consistenc'y of the reaction mixture (i. e. the Weight offiber per 100 parts by weight of solution) is maintained at a level suchas to afford ease of manipulation and thoroughness of treatment.

The optimum consistency is obviously dependent upon many factors,principally upon the method of handling the ber mixture. Thus, varyingVconsistencies may be used, depending upon whether the ber is treatedbatchwise, or continuously, as in counter-current operation.

It will be apparent that concentration, usage and consistency areinterrelated factors and that variations in one will aifect the others.Thus,

when the concentration and usage are varied,

the consistency also changes. Various combinations of these variablesare possible, the practical limiting factors being, as disclosed above,the desirability of keeping the operating conditions relatively mild,and also of providing consistencies such as to favor ease of handling,drying, processing and relatively complete separation of extract fromtreated material. A representative combination of these variablessuitable for use in extracting many Woods in fibrous form comprises theuse of an aqueous sodium hydroxide solution having a concentration of0.6% by weight sodium hydroxide in an amount equal to 15% by weight ofthe liber treated, whereupon the consistency of the mixture will beabout 4%.

As stated hereinabove, the alkaline extraction is carried out at atemperature which is preferably about the boiling temperature of themix- 7'5 tu're at normal atmospheric pressure. In ordinary operation, itis usually preferred, when batchwise extraction is being practiced, torecycle thealkaline solution used in the extraction. In this manner thedehydroperillic acid concentration isV built up in the alkaline solutionto a point where the said solution becomes an increasingly valuablesource thereof. Since some of the alkali is consumed by reaction withthe wood substance during the extraction process, it is desirable to adda further quantity of alkali before treating fresh wood fiber. in thecase of woods such as Western red cedar extracted at 4% consistency witha 0.6% solution of caustic soda, about 60% replacement of the originalcaustic alkali usage after each extraction is Sunicient to fortify thesolution to the desired degree, e. to a concentration of about 6.6% inthe case of caustic soda. Although the number of times an alkalinesolution which Yhas been thus fortied may be used for the'extraction ofraw wood is variable depending largely uponY the nature of thewoodfithas been observed that extracting eight times in the abovedescribed manner and fortifying the resulting extract with additionalalkali before each extraction results in the production of an alkalineextract rich in dehydroperillic acid, lignins andpolysaccharides-other-thanfcellulose and, at the same time, leaves afiber residue of useful composition and properties.

Recycling, or its equivalent operation, may be profitably practiceduntil the contribution of dehydroperillic acid of each new batch offiber equals the amount of dehydroperillic acid retained by the iibersupon separating the bers and the extract. Obviously, this involves manyfactors including the amount of dehydroperillic acid contributed by eachsuccessive batch of fiber as well as the emciency of the mechanical stepof eiecting the separation.

Similarly, the operating procedures hereinabove outlined for theprocessing of the aqueous alkaline extract resulting from the treatmentof the lignocellulose material with a dilute aqueous solution of analkali-metal hydroxide may be varied within'limits. It is a primaryobjective of the procedure, however, to provide conditions which willachieve the difficult function of separating the desired dehydroperillicacid product in a relatively pure form, uncontaminated by substantialquantities of the other constituents of the complex extract from whichit .is isolated, ie. uncontaminated bypolysaccharides-other-thancellulose, mineral salts such as sodiumsulfate, and, particularly, lignin. Thus, although it may be possible insome cases to separate the dehydroperillic acid from the extract withoutthe prior separation of lignin l-c.' as by acidification of the saidextract directly to a ph. of about 5, followed byA concentration thedesired degree and separation of the dehydroperillic acid from theprecipitated lignin, it has been found that a more sharply definedseparation of lignin from dehydroperillic acid and a purer product areobtained when the extract is freed from some of the lignin products, i.e., lignin lea, before the separation of the dehydroperillicacid iseffected.- Various acids may be used at step l l' for neutraliaing thedehydroperillic acid-containing extract. Any of the common mineralacidssuch as sulfuric acid, phosphoric acid, or hydrochloric acid, aswell as some ofthe organic acids, e. g. acetic acid, are suitable forthis purpose. Sulfuric acid is a preferred member of this group.

The amount of acid used is likewise variable, andY depends largely uponthe alkalinity of the extract. In general, enough acid is employed toresult in the formation of asubstantially neutral solution, i. e. onehaving a pH of about '7.

As stated, the neutralized extract is preferably concentrated to a pointat which lignin l-a is insoluble, but at which the dehydroperillic acid,polysaccharides-other-than-cellulose, and inorganic salt content of theextract, principally sodium sulfate whencaustic soda and sulfuric acidare used in the extraction and acidication steps, and some other ligninproducts are substantially soluble. There is thus removed from theextract a substantial amount of lignin products of relatively lowacidity, thereby simplifyingV the separation of the dehydroperillic acidat a later stage. Although the point at which this desideratum isattained varies with the relative proportions of solvent and solutes andwith other factors, when the proportions and operating con- Y drawing,wherein theaqueous solution remaining after separation of lignin l-a, isYaciduded to a pI-l oi about 5, is likewise subject to variation withinlimits. It is the general'objective of this step to acidify the solutionto a point at which the dehydroperillic acid, up to this stage of theprocedure in the form of a water-soluble salt, is converted to the freeacid, which is insoluble in cold water, without effecting theprecipitation of lignin products in amount suiiicient to make theseparation of the dehydroperillic acid in a relatively pure statediihcult, if not impossible. It has been discovered thatacidication to apH of between about and 6 usually accomplishes this purpose, a pH ofabout 5 being a preferred value. The acidication may be effected usingany suitable acid of suiiicient strength to reduce the pH of thesolution to the desired level. Sulfuric acid is a preferred reagent forthis use.

Step 28 has for its general object the coagulation of the ligninproducts which, together with dehydroperillic acid, almost invariablyprecipitates upon acidication of the solution to pH 5. The desiredcoagulation may be secured by warming the suspension, for example tofrom about 55 C. to about 75 C., preferably about 65 C. This step causesa large part'of the lignin product to aggregate and settle to the bottomof the containing vessel, thus leaving a supernatant liquid containingas suspended crystals the desired dehydroperillic acid, together withsome finely dispersed lignin product, and dissolved inorganic salts andpolysaccharides-other-thancellulose. Upon cooling, a further quantity ofdehydroperillic acid separates. During the process of cooling thedehydroperillc acid forms crystals which are considerably larger in sizethan are the suspended lignin product particles. They may, therefore, beseparated therefrom by pouring the supernatant liquid through any suit`able typeof lterhaving a mesh size such that amara? 9 the ligninproduct; particles pass therethrough but the dehydroperillic acidcrystals are retained upon the lter. The desiredl separation is thuseffected.

Purification of the crude dehydroperillic acid, obtained as above, maybe accomplished, as is indicated at step 33 in theV drawing, by washingone or more times with a solvent comprising cold water. Alternatively,the purication may be effected by dissolving the dehydroperillic acidproduct in a suitable solvent and recrystalliz- `ing it therefrom.Alternatively, also, it may be dissolved in an aqueous solution of asuitable alkali, such as sodium hydroxide, thereby forming an aqueousalkaline solution of the dehydroperillic` acid salt', asl sodiumdehydroperillate, which may be reprecipitated as the free acid in aArelatively pure state by acidification of the solution to a pH of about5. Sublimation aiords another method of purication.

It is to be understood that the term lignin product is used herein todesignate lignin products obtained byl chemical treatment oflignooellu'lose materials, although it is recognized that the ligninthus produced may have been altered in form or properties to a greateror lesser degree by reaction with the chemicals with which it has beentreated.

The process of the invention is illustrated by the following example,wherein the parts are expressed as parts by weight:

Example parts by weight of ber per 100 parts of solution.

The extraction was effected at the boiling temperatures of the solutionat about normal atmospheric pressure forV a duration of one hour. Theber was then separated from the sodium hydroxide solution and Washedwith water for sub- I sequent uses. The alkaline extract was fortied bythe addition of caustic soda in an amount sunicient to build up thesodium hydroxide concentration to a level substantially that of theoriginal solution. This required replacement of about 60% of theoriginal sodium hydroxide. The fortified solution was then employed inthe extraction of a further quantity of raw wood fiber. A total of eightextractions of raw wood fiber was carried out in this manner,replenishing the concentration of sodium hydroxide in the extractingsolution after each extraction. This resulted in the production of analkaline extract containing dehydroperillic acid and other materialsremoved from the wood substance.

Y This alkaline extract, which had a pI-I of about 10.y was thenprocessed for the recovery of its dehydroperillic acid content byneutralizing with sulfuric acid and concentrating by evaporation whileadding further sulfuric acid` as necessary i to maintain the solutionneutral. The solution was thus concentrated to` about 12% of itsoriginal volume. lIt was then cooled and filtered. This resulted in theseparation of lignin products 1-a.

cri

The filtrate, resulting from the separation of lignin l-a was acidied toa pH of 5, thereby precipitating dehydroperillic` acid, together with aquantity of another nely divided lignin product. This mixture was heatedto a temperature of C., andA then allowed to cool slowly. This causedmost of the lignin product to coagulate and settle to the bottom of thecontaining vessel within a few hours. After this treatment, the liquidabove the coagulated lignin product contained a fine dispersion oflignin product particles together with relatively large crystals ofdehydroperillic acid. It was decanted through Va coarse filter, therebyeffecting the separation of the dehydroperillic acid. Purification ofthe latter was effected by merely washing on the filter with cold water.

The product as thus produced was a white, crystalline solid having amelting point of about 88 C. Color tests with ferrie chloride reagentwere negative, indicating that the product was not a phenol. Thepresence of at least one carboxyl group was indicated by the fact thatthe product Was soluble in sodium bicarbonate to give a solution fromwhich it could be reprecipitated by acidification. No methoxyl groupswere present. The neutral equivalent was determined to be 159. Thisvalue, coupled with the empirical formula (CsHcO as determined fromcarbon-hydrogen analysis data, indicates the molecular formula to beC1QH12O2. This corresponds to the formula for dehydroperillic acid asgiven above.

Two derivatives of the above described acid product were prepared. Themethyl ester melted at 34 C. to 350 C. and boiled at 104 C. to 106 C.

The anilide, prepared by reaction of the acid or of its acyl derivativeswith aniline, Was a crystalline compound melting at 96 C.

It is apparent that the process of the present invention has manifoldadvantages. In. the rst place, it accomplishes the isolation of a pure,well defined organic chemical compound from Wood substance. Itrepresents for the iirst time a commercial process for the production ofdehydroperillic acid. It makes available at relatively 10W cost a newand useful chemical product, which has many potential applications perse, or as a starting material for the processes of the syntheticchemical industry. Finally and broadly, it represents a successfuleffort to obtain a useful chemical lay-product from a mild-controllableprocedure for the fractionation of wood substance.

Having now described my invention and in what manner the same may beused, what I claim as new and desire to protect by Letters Patent is:

1. The process for treating lignocellulose material for the recovery ofdehydroperillic acid and lignin precincts, comprising treating alignocellulosic source material for said acid and liguin with an aqueoussolution of a basic-acting compound of an alkali metal at a temperatureof from about normal room temperature to about the boiling point of saidsolution at atmospheric pressure and-in concentration sufficient toprovide not substantially more than about 15 parts by weight ci saidalkali metal compound per 100 parts of dry lignooellulose material forforming an extracted mass of said material and an' adueous alkalineextract containing dehydroperillic acid and lignin product, separatingthe said mass from the said extract, `substantially neutralizing saidalkaline extract and conditioning it by establishing a` saltconcentration sufficient to eiect "precipitation of a substantial amountof lignin products, separating the precipitated lignin products therebyleaving a residual extract, acidifying the residual extract to a pl-lvalue of between i kand 6 for precipitating dehydroperillic acid andlignin, and separating the thus precipitated dehydroperillic acid fromthe co-precipitated lignin and acidiiied lignin-containing extract.

2. The process for treating lignocellulose material for the recovery ofdehydroperillic acid and lignin products, comprising treating a sourcematerial for said acid and lignin with an aqueous solution Vof abasic-acting compound of an alkali metal at a temperature of from aboutnormal room temperature to the boiling point of said solution atatmospheric pressure and in concentration `sufficient to provide notsubstantially more than about V15 parts of said alkali compound per 100parts of dry lignocellulose material for a time period Ysufiicientsubstantially to exhaust the action of the solution for forming anextracted mass of said material and an aqueous alkaline extractcontaining dehydroperillic acid and lignin product, separating the saidmass from the said extract, substantially neutralizing said alkalineextract and conditioning iteby establishing a salt concentrationsuiicient to effect precipitation oi a substantial amount of ligninproducts, separating the precipitatedilignin products thereby .leavinga'residual neutral extract, acidiiying the residual extract to a pHvalue of between 4 and 6 for precipitating dehydroperillic acid andlignin, Vand separating the precipitated dehydroperillic acid from anycti-precipitated lignin and' Ylignin products, comprising treating asource material Yfor said acid and lignin with an aqueous solution of Vahydroxide of an alkali metal at a temperature of from about normal roomtemperature to about the boiling point of said solution at Y atmosphericpressure and in concentration suf- Ycient to provide not substantiallymore than about l5 parts of said alkali compound per l0() parts of drylignocellulose material for forming an extracted mass of said materialand anadueous alkaline extract containing dehydroperillic -ltween-Ll and6 for precipitating dehydroperillic acid, and separating the thusprecipitated Vdehydroperillic acid from any (zo-precipitated lignin Vandthe acidiiied lignin-containing extract.

, 4. The process for treating lignocellulose material for the recoveryof dehydroperillic acid and taining dehydroperillic acid and ligninproducts, separating the said extract from the extracted material,neutralizing the said extract and conditioning it by establishing a saltconcentration sufiicient to effect the precipitation of a substantialamount of Vlignin products, separating the precipitated lignin productsfrom the residual neutrai solution, acidiiyiing the residual neutralsolution to a pl-I of between 4 and 6 for precipitating dehydroperillicacid, and separating the precipitated dehydroperillic acid from anyco-precipitated lignin products and from the residual acidifiedsolution. 5. The process for treating lignocellulose material for therecovery of dehydroperillic acid and lignin products, comprisingtreating a source Inaterial for said acidrand lignin products VWith anaqueous solution of aY basic-acting compound of an alkali metal at atemperature of'from about, normal room temperature to the boiling pointoi'V said solution at atmospheric pressure and in concentrationsufcientto provide not substantially conditioning it by establishing aV saltconcentra,-Y

tion sufcient to eiect the precipitation of a substantial amount oflignin products, separating the precipitated lignin products from theresidual neutral solution, acidiiying the residual neutral solution to apl-I ot-between 4 and 6 for'precipitating additional nely divided ligninYproduct particles and relatively large crystals of, dehydroperillicacid, Vand filtering the resulting aqueous suspension through afiltering means having a rnesh size such as to permit the passage of theaqueous medium and 'of the finely divided lignin product particles butto retain the dehydroperillic acid crystals.

6'. Aprocess for the production'roi dehydroperillic acid and ligninproducts from Wood, which comprises treating comminuted Woodwhich isY asource material for said acid and-lignin with an aqueous solution of analkali metal hydroxide at a temperature of from about normal roomteinperature to the boiling point of said solution at i atmospheric'pressure and in concentration sui-f ncient to provide not substantiallymore than about l5 parts of said alkali metal hydroxide per Y 100partsof dry wood for a time period suicient substantially to Yexhaustthe action of the said: solution for forming anextracted'Inassrroi"Woodl and an Yaqueous alkaline extract containingde-V Y hydroperillic acid and ligninv products, separating ligninproducts, comprising treating a source material for'said acid and ligninproducts with an Y aqueous solution of an alkalimetal carbonate at Y atemperature of from about normalroom telnperature to the boiling pointoi said solution at atmospheric, pressure and in concentrationsuivlcient substantially to exhaust'the action of said solution forforming an extracted mass of said Vmaterial and an aqueous alkalineVextract conthe said extract from the extracted liber, substan- Ycipitated ligninr products from the vSaid solution,

acidiiying said neutral solution to a pH value of y between about 4 and6, and'separating the' thus precipitated dehydroperillic acid from .anycocontaining solution.

WILLIAM G. VAN BECKUM.

' No references cited

6. A PROCESS FOR THE PRODUCTION OF DEHYDROPERILLIC ACID AND LIGNINPRODUCTS FROM WOOD, WHICH COMPRISES TREATING COMMINUTED WOOD WHICH IS ASOURCE MATERIAL FOR SAID ACID AND LIGNIN WITH AN AQUEOUS SOLUTION OF ANALKALI METAL HYDROXIDE AT A TEMPERATURE OF FROM ABOUT NORMAL ROOMTEMPERATURE TO THE BOILING POINT OF SAID SOLUTION AT ATMOSPHERICPRESSURE AND IN CONCENTRATION SUFFICIENT TO PROVIDE NOT SUBSTANTIALLYMORE THAN ABOUT 15 PARTS OF SAID ALKALI METAL HYDROXIDE PER 100 PARTS OFDRY WOOD FOR A TIME PERIOD SUFFICIENT SUBSTANTIALLY TO EXHAUST THEACTION OF THE SAID SOLUTION FOR FORMING AN EXTRACTED MASS OF WOOD AND ANAQUEOUS ALKALINE EXTRACT CONTAINING DE-